Where does Avimor’s water come from?

Police, fire and emergency medical services aren’t the only necessities developers need to grapple with when building a segment in the Boise Foothills.

Avimor is a growing community that spans the Ada, Boise and Gem county lines and hopes to build nearly 10,000 homes over the next few decades. In addition to the necessary road improvements, businesses, community centers and the homes themselves, developer Dan Richter had to build a water system to serve homes along Highway 55. Between the wells portfolio, the property’s surface water rights date back more than a century, and with Suez’s push, Richter said nearly the entire project will be supplied by water from the property’s ground, with additional surplus water.

[ICYMI 2021: The Boise River: nature, development, and water quality shape its future]

“We do have Aviemore wells and Aviemore water rights to support all of our development,” Richter told Eagle City Council at a special meeting in November on the possible economic impact of a merger .

Where does the water come from now?

Avimor’s first homes were approved by Ida County in 2007.

Since then, 659 homes have been built and another 59 are under construction. By the time this phase is complete, 839 homes will be built on land that was once a foothill ranch. Boise County approved another 1,700 homes last year. Construction on this phase has yet to begin due to the looming question of whether Eagle City will choose to incorporate the community within city limits and gain land-use control of the project or leave it to Ida County.

Richter expects to apply to Eagle soon.

Aviemore, Idaho
A row of houses overlooking Aviemore Pond. Margaret Carmel/BoiseDev

The original plan was to provide well water for the first homes, but exploratory drilling found high levels of arsenic in the Sandy Hill aquifer unfit for drinking. Richter said the region’s aquifers are located in granite bowls below the surface, isolating naturally occurring arsenic from other sources of water.

To address this, the Idaho Public Utilities Commission allowed Suez Water to divert water from Treasure Valley and supply 839 homes through its system. The commission asked Avimor to pay for the construction of the water main until it was developed. In addition to the Suez pipeline, Avimor also owns surface water rights from the property’s two creeks and the ranch homestead used to irrigate the open space.

What’s next?

Richter expects the project to use groundwater for all of its remaining phases.

So far, Avimor has received water rights from the Idaho Department of Water Resources to pump 5 cubic feet per second, or up to 3.2 million gallons per day, from the well to service its properties. Richter said Avimor purchased five additional CFS applications from third parties, but they have not yet been approved. Once Avimor has used all of its first water rights and has demonstrated a need for a second water right, an application can be made, he said. He estimates that the entire 9,700-family program will only require a total of six CFSs. Under an agreement with IDWR and the City of Eagle, if the land is annexed, the water rights will go to the city.

Richter says a big reason Avimor’s homes don’t need much water is because of the project’s construction. There is a limit to how much grass a house can have. The rest of the landscape is dried with low-water drip irrigation, and each home is equipped with water-saving appliances and water heaters.

“I’ve worked for 26 years in Arizona, where you learn to conserve water because it’s so much more expensive,” Richter said in an interview with BoiseDev. “If you want to irrigate your grass, it’s an extra $200 or $300 a month. We bring this thoughtful approach to water conservation to this project.”

Avimor also holds a water recycling license from the Idaho Department of Environmental Quality. This enables the community to treat sewage from its wastewater treatment plant and reuse it for irrigation in the park, saving the amount of water needed to pump it from the aquifer. Richter also wants to build a system where this circulating water gets additional treatment, pumped into the Sandy Mountains aquifer, stored there during the winter, and then reused for irrigation after the seasons. However, the aquifer storage and recovery system has not been approved by DEQ or IDWR.

Avimor needs to prove the aquifer is rising before it can get approval to pump the water back, Richter said. He hopes to get permission to reuse it sometime this year, but the application is still pending.

Enter: City of Eagles

If the development is incorporated into Eagle City, there will be some changes to the rules of how Avimor uses its water resources.

Under Eagle City regulations, if Avimor were to be incorporated into the city limits, it would need to hand over its wells, pipes and other elements of the water infrastructure system to the city to connect its municipal water system. This includes Avimor’s water rights up to 10 CFS if a second water rights application is approved.

Municipal governments, especially city governments, can obtain special kinds of water rights that allow water to be used for more purposes and in more flexible locations due to expected growth and changes over time. By granting the rights to the City of Eagle, it can be changed so that water drawn from Avimor’s wells can be used anywhere within the city’s service area. This also works in reverse, meaning that any water from the city can be pumped to the Avimor’s source.

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